RU2553833C2 - Nacelle for aircraft engine with nozzle of variable cross section - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: nacelle of an aircraft engine includes a sloping bonnet of a thrust reverser, a jet nozzle of a variable cross section and a device for bringing into action the bonnet and the nozzle. The jet nozzle is arranged in the downstream continued part of the bonnet and installed on the latter with a possibility of being shifted. The above devices include at least one power cylinder to actuate the bonnet of the thrust reverser, at least one drive gear installed in a turning manner on a fixed nacelle structure and at least one gear rack. The latter is attached to the nozzle and has a possibility of its actuation. The gear rack is engaged with the drive gear when the bonnet of the thrust reverser is in a forward thrust position and disengaged from the gear when the bonnet is in a reverse thrust position.

EFFECT: invention allows reducing the weight and simplifying the device actuating the jet nozzle and the thrust reverser bonnet.

7 cl, 18 dwg

Description

The invention relates to a nacelle for an aircraft engine with a nozzle of variable cross section.

As you know, the engine nacelle of the aircraft provides the direction of the outdoor air to the engine and the high-speed emission of this air with the necessary thrust.

In turbofan engines, the fan-blown air stream is separated after the fan into a primary stream (also called a “hot” stream), which enters the internal circuit of the turbojet engine, undergoing a series of compressions and one negative pressure there, and a secondary stream (“cold” stream), which circulates inside an essentially annular path, bounded on one side by the engine cowling (a fixed internal structure, also called IFS), and on the other hand, the diameter m of gondola.

The cold air stream leaving the nacelle through the jet nozzle, bounded by the downstream edge of the nacelle, provides the bulk of the thrust.

In order to optimize aerodynamic performance and thereby save fuel consumption, it is very advisable to be able to adjust the cross section of the air outlet outlet behind the nacelle - indeed, it is useful to be able to increase the specified section at the take-off and landing stages and reduce it at the cruising stages of the flight; such a technical solution is sometimes called an “adaptive nozzle” or “an adjustable fan nozzle” (PCB nozzle, VFN).

In addition, it is known that thrust reversers are often located in the nacelle, which ensure, during landing, the direction of part of the secondary air flow to the front or upstream side of the nacelle, which makes a significant contribution to aircraft braking.

Such thrust reversal means are often equipped with deflecting gratings, i.e., they contain a group of gratings located downstream of the fan casing along the perimeter of the cold flow circulation path, and these gratings are opened by command through the sliding hood of the thrust reverser mounted on the nacelle structure.

The secondary airflow outlet nozzle is located in the downstream extension of the thrust reverser hood, and it is important to ensure the possibility of independently actuating these two nacelle nodes, in particular, the task is to increase the nozzle cross section without actuating the thrust reverser, in particular, when taking off.

The prior art knows a number of technical solutions for actuating the nodes under consideration independently of each other.

One of the known solutions involves the use for these two nodes of independent drive power cylinders.

According to another solution, cylinders with two rods are used, with one rod actuating the hood of the thrust reverser and the other a jet nozzle.

According to yet another solution, power cylinders are used that drive only the jet nozzle, with controllable means for fixing the reverser hood with the nozzle provided that lock when the nozzle is at the end of the stroke downstream, which allows the thrust reverser hood to be actuated and unlocked after arrival thrust reverser hood back to the “direct thrust” position, which allows returning the jet nozzle to the upstream position.

The disadvantage of all these known solutions is, in particular, excessive weight, due to the fact that to ensure the independent actuation of the hood of the thrust reverser and the jet nozzle, separate power cylinders and / or fixing means are used.

The objective of the proposed invention is, in particular, the elimination of this drawback.

To solve this problem, an aircraft engine nacelle is proposed comprising a thrust reverser hood movable between a direct thrust position and a reverse thrust position; a variable cross-section jet nozzle located in a downstream extension of said hood; and means for actuating, respectively, said hood and nozzle, wherein the proposed nacelle is characterized in that said jet nozzle is mounted on said hood of a thrust reverser, with said thrust reversing means comprising:

at least one slave cylinder for actuating said thrust reverser hood;

at least one pinion gear mounted rotatably on a fixed structure of said nacelle;

at least one gear rack for actuating said jet nozzle attached to said nozzle, said gear rack meshing with said pinion gear when said thrust reverser hood is in direct thrust position and disengaging with said gear when said gear is located reverse hood in reverse thrust position.

The presence of these features allows you to set the jet nozzle independently of the hood of the thrust reverser by means of a rack-and-pinion gear type from a pinion and a gear rack, which is significantly simpler and has lower weight and dimensions relative to these various devices known from the prior art.

The claimed gondola may have the following additional features:

the specified nacelle is equipped with a group of power cylinders for actuating the specified hood of the thrust reverser, as well as a group of devices for actuating the specified jet nozzle containing a gear and a gear rack;

said devices containing a gear and a gear rack are located near the “12-hour” and “6-hour” beams of the fixed structure of the indicated nacelle — these beams, which are located respectively in the upper and diametrically opposite lower parts of the nacelle, allow installation in the usual way and displacement of the movable elements of the nacelle;

the specified nacelle is equipped with means for fixing the specified nozzle with the specified hood of the thrust reverser when the specified nozzle is in its extreme position downstream and when the hood of the thrust reverser is in the direct thrust position — these fixing means allow the jet nozzle to be displaced together with the thrust reverser hood under the action of the indicated power cylinders;

the specified nacelle is equipped with means to eliminate play between each gear and the corresponding gear rack - these tools to eliminate play provide unhindered gear engagement again with the teeth of the rack when the gear is returned to a position upstream under the action of displacement of the thrust reverser hood upstream;

said means for eliminating play include means for resiliently suspending said gear on a fixedly mounted nacelle structure;

said clearance means are provided with at least one roller with an axis parallel to the axis of said gear, adapted to bring said gear rack into contact with said gear.

Other features of the invention will be apparent upon reading the description below with reference to the accompanying drawings, in which:

figure 1 - image of the axial section of the rear of the claimed nacelle in cruising mode;

figure 2 - image of the rear in a perspective view;

figure 3 is a partial view of the rear of the nacelle in section by a plane P from figure 1-2;

4 is an image of a sliding mechanism of the rear of the nacelle;

5 is a schematic illustration of the rear in cruising mode;

6, 7, 8 - images similar to FIGS. 2, 4, 5, respectively, when the jet nozzle of the rear of the nacelle is in a position corresponding to take-off or landing;

Figures 9, 10, 11 are images similar to Figures 1, 2 and 4, respectively, when the rear of the nacelle is in the position corresponding to the thrust reversal;

12, 13, 14 are images similar to FIG. 5, schematically illustrating the various steps of moving the rear of the nacelle to the thrust reverse position;

Fig. 15 is a view similar to Fig. 4, schematically illustrating the return of the rear of the nacelle to the position of Figs. 6-8;

Fig. 16 is a view similar to Fig. 4, schematically illustrating the return of the jet nozzle to a position corresponding to the cruising mode;

17 and 18 are images similar to FIG. 3 illustrating two options for eliminating play between the pinion gear and the rack attached to the jet nozzle of the rear of the claimed nacelle.

Throughout the drawings, identical or similar item numbers refer to identical or similar components or assembly units.

All drawings are equipped with the XYZ coordinate system, the three axes of which represent the longitudinal, transverse and vertical directions of the nacelle, respectively.

It should be noted that the X axis is directed towards the upstream part of the nacelle, while the flow refers to the air flow that must pass through the nacelle during the working process.

It should also be noted that in the description below it is mainly about the rear of the nacelle, that is, about that part that is located downstream of the fan casing - since the invention relates to this area.

In addition, it should be noted that essentially only one half of the nacelle is described below, it being understood that the construction of the second half of the nacelle located on the other side of the suspension beam can be derived using the simple symmetry of the described half relative to a vertical plane parallel to the XZ plane.

Consider figure 1, depicting the rear of the claimed gondola in a cruise flight situation.

As shown in figure 1, the rear part of the nacelle includes a fixed internal structure 1, forming a fairing of a turbojet engine (not shown), centered around axis A, and a movable external structure 3, restricting the circulation path 5 of the secondary air stream 7 created by the fan (not shown) and flowing through the output cross section 9 with the provision of thrust of the aircraft.

In particular, the movable outer structure 3 comprises a radially inner movable part 11 forming a thrust reverser hood and a radially outer part 13 forming a nozzle of variable cross section.

On the hood 11 of the thrust reverser, the thrust reverse flaps 15 are pivotally mounted, each of which is connected to the fixed internal structure 1 by means of connecting rods 17.

Thrust reverse gratings 19 are also provided fixedly mounted on the front frame 21 having a substantially annular shape and fixed downstream of a fan casing (not shown).

In the cruise flight situation shown in FIG. 1, the thrust reverser hood 11 and the upstream part 23 of the jet nozzle 13 close the thrust reversal lattices 19. The flaps 15 of the thrust reverser are located in the continuation of the hood 11 of the thrust reverser, due to which the cold air stream 7 can freely circulate in the path 5.

In the reverse thrust situation shown in FIG. 9, both the thrust reverser hood 11 and the jet nozzle 13 are shifted downstream of the deflecting grids 19, as a result of which the thrust reversal flaps 15 rotate to a position transverse to the secondary flow circulation path 5, causing thereby deflecting and exiting the secondary air stream 7 outward through the grilles 19 in the direction of the upstream part of the nacelle.

Below is described in more detail the proposed technical solution, providing a transition from the position of figure 1 to the position of figure 9.

As shown in FIG. 3, the inner hood 11 of the thrust reverser is connected to the fixed inner structure 1 by means of a longitudinal beam 25 defining a first slide 27, inside which the first longitudinal slider 29 can move.

The jet nozzle 13 is attached to a second longitudinal slide 31, within which a second longitudinal slider 33 can move, itself rigidly connected to the first slide 29.

As is well shown in FIGS. 3-4, a toothed rack 35 extends along a second slide 31 and is adapted to interact with a gear 37 mounted on a shaft 39 of the engine 41 fixed to the protruding portion 43 of the beam 25.

It should be noted that such a node that provides directional movement of the PCB nozzle (VFN) can have a reverse configuration, that is, the slide can be integrated not with the longitudinal slider 33, but with the first longitudinal slider 29. In this configuration, the gear 37 can be driven in the upper plane relative to the axis of the slide.

In addition, you can choose another place to accommodate the rack and pinion, not a system of slide and slide, as the side structure of the jet nozzle 13.

As is now apparent from the description, the motor 41 can provide a displacement of the second slide 31 relative to the second slide 33, that is, the shift of the jet nozzle 13 relative to the inner hood 11.

In this case, the actuation of the inner hood 11 itself is provided by a group of power cylinders, one of which is shown in figure 2 under the position number 45. One of the ends of the specified cylinder is fixed to the front frame 21, and the other end to the inner hood 11.

The main components described above are shown schematically in FIG. 5, illustrating a configuration corresponding to the forward thrust mode and the cruising mode.

In this configuration, the inner hood 11 of the thrust reverser is in its upstream position and is closed to the front frame 21 by means of a first latch 46.

The power cylinders 45 are retracted.

The jet nozzle 13 is located upstream of the inner hood 11, that is, each of the drive gears 37 (in fact, two of them for each half of the gondola - one in the upper part of the half of the gondola and the other in the lower part) is located downstream of the corresponding her gear rack 35.

There is a second latch 47, which is configured to mount the jet nozzle 13 with the inner hood 11 and is in the open state.

This configuration corresponds to a cruise flight, during which, of course, the thrust reverser must be inactive, and the output cross section 9 of the nozzle 13 should be minimal.

We turn to the consideration of Fig.6-8, illustrating the situation corresponding to takeoff or landing.

In this case, you must be able to increase the cross section 9 of the jet nozzle 13, for which it is necessary to shift the specified nozzle downstream relative to the position in figure 1-5.

This is achieved by turning the gears 37 through the respective motors 41, resulting in a downward displacement of each gear rack 35 - as shown by arrow F in FIG. 7.

Thus, the jet nozzle 13 is moved to the downstream position shown in FIGS. 6 and 8. As for the inner hood 11 of the thrust reverser, it remains stationary.

Now, if it is necessary to obtain thrust reversal (see Fig. 9) for landing, it is necessary to open the first latch 46 and actuate the power cylinders 45 so as to provide a shift along the first slide 27 of the assembly formed by the inner hood 11 and the jet nozzle 13, as shown in FIG. 10.

In particular, as shown in FIG. 11, in which a simultaneous shift of both components is indicated by an arrow F, each gear rack 35 is disengaged from its corresponding pinion gear 37.

For even greater clarity, refer to FIGS. 12-14, which show the sequence of interaction of various components when moving to the thrust reverse position.

As shown in FIG. 12, the latch 46 is open, respectively, the jet nozzle 13 is in the downstream position.

Then, as shown in FIG. 13, the second latch 47 is closed to secure the jet nozzle 13 with the thrust reverser internal hood 11.

At the same time, the power cylinders 45 are activated, which allows a simultaneous displacement of the indicated hood and nozzle to their downstream position, as a result of which each gear 37 disengages from the corresponding gear rack 35 (see Fig. 14).

In the considered thrust reversal position, the action of the connecting rod 17 causes the thrust reverse flaps 15 to prevent the secondary flow from circulating in the path 5, as a result of which the secondary air returns outward in the direction of the front of the nacelle, as shown by arrow 7 in Fig. 9.

The claimed nacelle is returned to its initial state in two stages: as shown in Fig. 15, the power cylinders 45 are first retracted, thereby returning the assembly formed by the thrust reverser internal hood 11 and the jet nozzle 13 to the direct thrust position. This total displacement is indicated in FIG. 15 by arrow F.

Thus, each gear rack 35 is engaged again with a corresponding pinion gear 37.

Then, in order to return the jet nozzle 13 to its upstream position (with a small cross section corresponding to the situation of the cruise flight), the gears 37 are turned in the direction opposite to that of FIG. 7 by means of the respective engines 41 until the upstream part 23 of the jet nozzle 13 does not completely block the thrust reverse grating 19.

As follows from the above description, it is possible to independently actuate the internal hood 11 of the thrust reverser and the jet nozzle 13 using significantly lower weight means compared to the means known from the prior art — the dimensions and weight of the rack and pinion used are undoubtedly smaller than those of the known from the prior art systems with two power cylinders or with power cylinders with two rods.

An important aspect of the invention is the need to reliably ensure that each gear rack 35 is returned in engagement with the corresponding pinion gear 37, regardless of any loopholes and deformations that may occur.

To this end, a backlash elimination system should be provided, for example, containing, as shown in FIG. 17, a roller 51 freely mounted on a beam 25, having an axis 53 parallel to the shaft 39 of the engine 41, and configured to push the gear rack 35 leading to the specified rail in contact with the teeth of the gear 37, when the specified rack returns from the position of FIG. 11 to the position of FIG. 15.

As shown in FIG. 18, as an alternative, using the elastic suspension means 55, the motors 41 can be connected to a fixed beam 25 - while the gears 37 will rotate around a substantially vertical axis, that is, an axis parallel to the long side of the sheet of drawings 9 / 9.

Of course, the present invention is in no way limited to the embodiment described and illustrated here.

So, for example, to connect the internal hood 11 of the thrust reverser with the jet nozzle 13, you can do without a second latch 47 - it is established that the secondary air flow and external air independently tend to hold the jet nozzle 17 in a position that is most distant downstream from the inner hood 11 .

Claims (7)

1. A nacelle for an aircraft engine, comprising: a movable hood (11) of a thrust reverser movable between a direct thrust position and a reverse thrust position; a jet nozzle (13) of variable cross section, located in the downstream continuation of the specified hood (11);
and means for actuating, respectively, said hood (11) and said nozzle (13), characterized in that said jet nozzle (13) is mounted on said hood (11) of the thrust reverser with the possibility of shear, while said thrust reverser comprises:
at least one power cylinder (45) for actuating said hood (11) of a thrust reverser;
at least one pinion gear (37) mounted pivotally on a fixed structure (25) of said nacelle;
at least one gear rack (35) for actuating said jet nozzle (13) attached to said nozzle (13), said gear rack (35) being engaged with said pinion gear (37) when said hood is located ( 11) the thrust reverser in the direct thrust position and disengages from the specified gear when the specified hood (11) is in the reverse thrust position. 2. A nacelle according to claim 1, characterized in that it is equipped with a group of power cylinders (45) for actuating said hood (11) of a thrust reverser, as well as a group of devices for actuating said jet nozzle (13) containing a gear ( 37) and the rack (35). 3. A nacelle according to claim 2, characterized in that said devices comprising a gear (37) and a gear rack (35) are located near the “12-hour” and “6-hour” beams of the fixed structure of said nacelle. 4. Gondola according to any one of claims 1 to 3, characterized in that it is equipped with means (47) for fixing said nozzle (13) with said hood (1) of a thrust reverser when said nozzle (13) is in the extreme position downstream and when the hood (11) of the thrust reverser is in the direct thrust position. 5. A nacelle according to any one of claims 2 to 3, characterized in that it is equipped with means to eliminate play between each gear (37) and the corresponding gear rack (35). 6. Gondola according to claim 5, characterized in that said means for eliminating play include means (55) for elastic suspension of said gear (37) on a fixed structure (25) of the nacelle. 7. Gondola according to claim 5, characterized in that said means of eliminating play are provided with at least one roller (51) with an axis (53) parallel to the axis (39) of said gear (37), adapted to bring said gear rack ( 35) into contact with said gear (37).

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